Water heater hard wire

[FredSly]

In what year or code change cycle did hard wiring 240 v water heaters go into effect and do retro fit water heaters need to meet the newer code.

[Jerry Peck - Codeman]

In what year or code change cycle did hard wiring 240 v water heaters go into effect and do retro fit water heaters need to meet the newer code.

I kept going back in my NEC collection and ... going back further ... and further ... and further ... then I went back to my 1905 NEC, and while the wording has changed over the editions, flexible cords on water heater was never allowed (after typing in the 1905 NEC, I will go back to the original 1897 NEC (the 1897 NEC is considered as "the first National Electrical Code").
- From the 1905 NEC: (bold is mine)
- - 28. Flexible Cord.
- - - a. Must have an approved insulation and covering (see No. 45).
- - - b. Must not be used where the difference of potential between the two wires is over 300 volts.
- - - c. Must not be used as a support for clusters.
- - - d. Must not be used except for pendants, wiring of fixtures, portable lamps or motors, and portable heating apparatus.
- - - - (includes several paragraphs describing work, not applicable to this, so I did not include them)
- - - e. Must not be used in show windows.
- - - f. Mus be protected by insulation bushings where the cord enters sockets.
- - - g. Must be so suspended that the entire weight of the socket and lamp will be borne by by some approved device under the bushing in the socket, and above the point where the cord comes through the ceiling block or rosette, in order that the strain may be taken from the joints and binding screws.
- - - - (includes this note: This is usually accomplished by knots in the cord inside the socket and rosette.)

Jerry's comments:
- a.: a cord construction requirement
- b.: a voltage limitation
- c.: not applicable to water heaters
- d.: "Must not be used except for" ... water heaters are not one of the "except for" items such as: "pendants"; nor are water heaters "wiring of fixtures"; nor are water heaters "portable" (as in "portable lamps or motors" or "portable heating apparatus")
- e.: not applicable to water heaters
- f.: not applicable to water heaters
- g.: not applicable to water heaters

Thus, even in the 1905 NEC, flexible cords were not allowed to be used for water heaters.

The 1897 NEC wording is essentially the same for requirements and limitations; however, it includes additional wording and details which were later dropped.